In the prior art, various types of electrical circuit arrangements have been utilized for temperature sensing or temperature measurement. Such devices may utilize for example the changes in frequency of free-running oscillation of a ring oscillator circuit, i.e. changes which depend upon the variation of characteristics of transistor elements of the ring oscillator circuit due to temperature changes. However the output signals indicating temperature variations which are produced by such a circuit are non-linear with respect to temperature, and in addition the relationship between such signals and temperature is not an absolute one, i.e. it is dependent upon the particular characteristics of the elements used for temperature sensing, and hence it is generally necessary to provide external adjustment means with such a circuit to provide any degree of measurement accuracy.
There is therefore a requirement for an electronic temperature sensing device which will produce output signals which are linearly related to temperature variations in an absolute manner, i.e. which does not require adjustment. Such a device is made possible by the present invention.